Thiazolylmercaptoalkanediones



United States Patent THIAZOLYLIVIERCAPTOALKANEDIONES John J. DAmico, Charleston, W. Va., assignor to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware No Drawing. Application November 25, 1952, Serial No. 322,571

12 Claims. (Cl. 260-306) The present invention relates to a new class of polyfunctional compounds characterized by the presence of a mercaptothiazolyl group and at least two carbonyl groups as for example thiazolylrnercapto acetoacetates. The invention also relates to the preparation of these compounds.

The new class of compounds possess the structural formula O=(IJR'( where T represents a thiazolyl group, R represents an alkylene group, R represents an alkyl or 'alkoxy group and R represents a hydrocarbon group. Suitable examples of thiazolyl groups are 4,5-dimethyl thiazolyl, 4- methyl thiazolyl, naphtho thiazolyl, 5-chlorobenzothiazolyl, 4-ethyl thiazolyl, 4,5-diethyl thiazolyl, 4-methyl benzothiazolyl, phenyl benzothiazolyl, 4propyl thiazolyl, 4-butyl thiazolyl, S-carbomethoxy 4-rnethyl Z-thiazolyl, 5.-carboethoxy 4-methyl 2-thiazolyl, S-carbobutoxy 4-methyl Z-thiazolyl and 4-methy1 S-acetyl thiazolyl groups. Suitable alkyl groups are ethyl, propyl, isopropyl, butyl, isobutyl, tert.-butyl, amyl, hexyl, octyl, and decyl groups. Suitable alkoxy groups are illustrated by propoxy, isopropoxy,- amyloxy, heptyloxy and nonyloxy groups.

These compounds may be prepared by condensing a mercaptothiazole with a halogenated alkylene dicarbonyl compound in which the halogen is attached to a carbon atom adjacent to one carbonyl group and not more than one carbon atom removed from the other. Halogen halide or metal halide is removed in the condensation resulting in the formation of the desired products. Suitable reactants include ethyl a-chloro acetoacetate, ethyl :x-ChlOlO a-propionyl propionate, a-chlOrO butyl acetic ester CHaCHzCHaCOCI-ICICOOR, a-ChlOIO propionyl acetic acid ester i C2H5G-UHC1COOR ot-ChlOlO u-butyryl butyric acid ester ii i if CzH5C-(iCOCz s Calls a-chloro a-heptoyl heptylic acid ester u i i CH3(GH:)50-O-UOC2H5 m s ct-chloro heptoacetic ester ethyl a-chloro trichloro acetoacetate t r t o ono-o-o-o our,

a-chloro acetoacetic methyl ester, ot-ChlOIO methyl acetoacetic methyl ester, a-chloro ethyl acetoacetic methyl ester, OL-ChlOI'O ethyl 'acetoacetic ethyl ester, a-chloro butyryl acetic methyl ester and a-chloro decanoyl acetic ethyl ester.

The following examples illustrate in detail the preparation of the new compounds.

EXAMPLE 1 A solution of potassium Z-rnercaptobenzothiazole was prepared by mixing 95-grams (0.55 mole) of 97% 2-mercaptobenzothiazole, 30.8 grams (0.55 mole) of potassium hydroxide, 550 ml. of acetone, and 22 grams of water. To this stirred solution 90.5 grams (0.55 mole) of ethyl ot-ClllOl'OiCfliOflCfiifilC was added. An exothermic reaction set in, the temperature rising from 30' to 52 C. within 5 minutes. The reaction mixture was stirred for 8 hours, and let stand for an additional 8 hours. The potassium chloride was recovered by filtration. The acetone was removed by distillation. The residue contained two layers which were separated. The organic layer was dried over Attapulgus clay, and any unreacted ethyl tx-chloroacetoacetate was removed in vacuo. A yield of 144 grams (90%) of ethyl a-(2-benzothiazolylmercapto)acetoacetate, an amber colored oily product was obtained. Calcd. for C13H13NO3S2 EXAMPLE 2 A solution of potassium Z-mercaptobenzothiazole was prepared by mixing 86.2 grams (0.5 mole) of 97% 2-mercaptobenzothiazole, 28.05 grams (0.5 mole) of potassium hydroxide, 700 ml. of acetone, and 22 grams of water. To this stirred solution 111.5 grams (0.5 mole) of ,B-bromoethyl levulinate was added. An exothermic reaction set in, the temperature rising from 30 to 48 C. within 5 minutes. The reaction mixture was stirred for 6 hours, and let stand for an additional 8 hours. The potassium chloride was recovered by filtration. The acetone was removed by distillation. The residue contained two layers which were separated. The organic layer was dried over Attapulgus clay and any unreacted ,B-bromoethyl levulinate was removed in vacuo. A yield of 144 grams (93 of ethyl fi-(2-benzothiazolylmercapto)-levulinate, an am- EXAMPLE 3 A solution of potassium Z-mercaptobenzothiazole was prepared by mixing 86.2 grams (0.5 mole) of 97% 2- mercaptobenzothiazole, 28.2 grams (0.5 mole) of potassium hydroxide, 500 ml. of acetone and 22 grams of water. T 0 this stirred solution 96.32 grams (0.5 mole) of butyl a-chloroacetoacetate was added. An exothermic reaction set in, the temperature rising from 25 to 52 C.

Calcd., Foimd percent percent Nitrogen 4. 33 4. 46 Sulfiu- 19. 83 20.18

EXAMPLE 4 A solution of potassium Z-mercaptobenzothiazole was prepared by mixing 95 grams (0.55 mole) of 97% 2- mercaptobenzothiazole, 30.8 grams (0.55 mole) of potassium hydroxide, 2000 ml. of acetone and 22 grams of water. To this stirred solution 75.3 grams (0.5 mole) of methyl ot-chloroacetoacetate was added. An exothermic reaction set in, the temperature rising from 28 to 49 C. within minutes. The reaction mixture was stirred for 8 hours, and let stand for an additional 8 hours. The potassium chloride was recovered by filtration. Upon removal of the acetone a solid resulted. The precipitate was diluted with 500 ml. of water, filtered, washed with water until free of chloride, and dried at 50 C. The product, methyl ot-(2-benzothiazolylmercapto) acetoacetatc, M. P. 99-101 C., was obtained in 98% yield. After recrystallization from ethyl alcohol, it melted at EXAMPLE 5 A solution of potassium Z-mercaptobenzothiazole was prepared by mixing 95 grams (0.55 mole) of 97% 2- mercaptobenzothiazole, 30.8 grams (0.55 mole) of potassium hydroxide, 1000 ml. of acetone and 22 grams of water. To this stirred solution 67.28 grams (0.5 mole) of 3-chloro 2,4-pentanedione was added. An exothermic reaction set in, the temperature rising from 28 to 48 C. within 5 minutes. The reaction mixture was stirred for 8 hours and let stand for an additional 8 hours. The potassium chloride was recovered by filtration. Upon removal of acetone, a solid resulted. The precipitate was diluted with 500 ml. of water, filtered, washed with water until free of chloride, and dried at 50 C. The product, 3 (2 benzothiazolylmercapto)-2,4-pentanedione. M. P. 94-96 C. was obtained in 95.9% yield. After recrystallization from ethyl alcohol, it melted at 104-l05 C. Calcd. for C12H11NO2S2 Calcd., Found,

percent percent Nitrogen 5. 28 5. 19 Sulfun- 24.17 23. 98

rubber are illustrated by the following test. Rubber compositions were compounded comprising Stock A B Smoked sheets parts by weight" 100 Zine oxide .do. 5 5 Stearie acid (lo 1 1 Sulfur do.. 3 3 Ethyl a-(Z-benzothiazolylmercapto) acetoace tate. do 1 0. 7 Diphenyl guani'dine do O. 3

The compositions were vulcanized in the usual manner by heating in a press for different periods of time at 135 C.

Table l Modulus of Cure Elasticity in Tensile at Ultimate Stock Time in lbs/in. at Break in Elongation,

Mins. Elongation lbs/in. percent Other compositions were compounded comprising Stock C D Pale crepe rubber parts by weight" 100 100 Zinc oxide do 5 5 Stearic acld do 1 l Sulfur do .3 d 3-(2-Benzothiazolylrnercapto)-2,4-pentanedionc (lo l Methyl a (2 benzothiazolylmercapto) acetoacetate do 0. 7

The stocks were vulcanized by heating in a press at C. The physical properties of the vulcanizates are set forth below:

Table II Modulus of Ultimate Cure Elasticity in Tensile at Elonga- Stock Time in lbs/in. at Break in tion,

M ins. Elongation lbs/in. Percent copolymer of butadiene-1,3 and styrene. Compositions were compounded comprising Stock I E F Synthetic rubber "parts by weight" 100 100 Carbon black do. 50 50 Saturated hydrocarbon softener do 10 10 Zinc oxide do 4 4 Stearic acid. do 2 2 Sulfur do 1.75 1.7-3 Acetone/p-amino biphcnyl condensation product ..do 1. 5 I. 5 3-(Z-Benzothiazolylmereapto)-2,4-pentanedione do. 0. 7 Diphenyl guanidine do.. 0. 5 .05 Methyl a-(2-benzothiazolylmereapto)aeetoacetate do 0. 7

The compositions were vulcanized by heating in a press for 90 minutes at 144 C. The physical properties are set forth below:

Table III Modulus of Ultimate Elasticity in Tensile at Elonga- Stock lbs/in. at Break in tion,

Elongation lbs/in. Percent It is intended to cover all changes and modifications of the examples of the invention herein chosen for purposes of disclosure which do not constitute departures from the spirit and scope of the invention.

What is claimed is:

1. A compound of the structure O=O-R" where T represents a radical selected from the group consisting of 4,5-di(lower alkyl) Z-thiazolyl, 4-(lower alkyl) 2-thiazolyl, arylene hydrocarbon Z-thiazolyl containing less than 14 carbon atoms, chloro substituted Z-benzothiazolyl, 4-(lower alkyl) S-(lower carboalkoxy) 2-thiazolyl and 4-(lower alkyl) S-acetyl 2-thiazolyl radicals, R represents a lower alkylene group, R is selected from the group consisting of alkyl radicals containing less than 11 carbon atoms and alkoxy radicals containing less than carbon atoms and R represents an alkyl radical containing less than 10 carbon atoms.

2. A compound of the structure where R represents an alkylene group of less than three carbon atoms, R and R" represent alkyl groups containing less than 11 carbon atoms.

3. A compound of the structure Where R represents an alkyl group of less than 11 carbon atoms.

4. A compound of the structure where R represents an alkyl group of less than 5 carbon atoms.

5. Ethyl a(2-benzothiazolylmercapto)acetoacetate.

6. Ethyl 5-(2-benzothiazolylmercapto)levulinate.

7. Bu-tyl ot-(2-benzothiazolylmercapto)acetoacetate.

8. Methyl w(Z-benzothiazolylmercapto)acetoacetate.

9. 3-(Z-benzothiazolylmercapto)-2J,4-pentanedione.

10. The process which comprises condensing a mercaptothiazole from the group consisting of 4,5-di(lower alkyl) 2-mercaptothiazoles, 4-(lower alkyl) Z-mercaptothiazoles, arylene hydrocarbon 2-mercaptothiazoles containing less than 14 carbon atoms, chloro substituted 2- benzothiazoles, 4-(lower alkyl) S-(lower carboalkoxy) Z-mercaptot-hiazoles and 4-(lower alkyl) S-acety-l Z-mercaptothiazoles with a halogenated alkylene dicarbonyl compound of the structure i i i O-RCR.

Where R represents a lower alkyl group, R is selected from the group consisting of alkyl groups containing less than 11 carbon atoms and allcoxy groups containing less than 10 carbon atoms and R" represents an alkyl radical containing less than 10 carbon atoms.

11. The process which comprises condensing mercaptobenzothiazole with an oc-chloroacetoacetate.

12. The process which comprises condensing mercaptobenzoth-iazole with a fl-halogen substituted ester of levulinic acid.

Williams July 27, 1937 Orthner Nov. 15, 1938 

1. A COMPOUND OF THE STRUCTURE 